Abstract

We have studied the carrier profile and calculated a unique effective mass for a two-dimensional
hole gas confined in a SiO2/Si/Si1_xGex/Si structure when an external
voltage is applied. For this purpose, we have solved the system of differential equations
provided by the 6 x 6 Luttinger Hamiltonian [1] simultaneously with the Poisson
equation, applying an iterative process until convergence was achieved. This enabled us
to incorporate the warping and the strong coupling among the subbands that constitute
the band structure [2].

From the calculated density of carriers we were able to evaluate an average effective
mass. Although our calculations indicate that this effective mass varies notably with the
hole confinement level, in general, we observed a decrease in the calculated effective
mass as the molar fraction of Ge increases, which might justify the use of this kind of
device.